The invention relates to speech processing systems for use with marine navigational equipment.
Present marine navigational equipment, such as LORANs, global positioning systems (GPS), satellite navigational systems (SATNAV), depth sounders, temperature gauges, and digital compasses etc., provide output information via displays and/or serial digital output signals.
Display outputs on navigational equipment require that a viewer be positioned to view the display when the navigational information is desired. This is not always possible, particularly when the one or more persons on the boat are each busy with other activities, such as pulling nets or lobster traps, or controlling the movement of the boat in adverse weather conditions.
Although attempts have been made to provide speech output from navigational equipment, such devices have been unsatisfactory either because the devices are slow and expensive, or because they are too limited and inflexible. Devices that speak or spell words or characters as they are received from an input string such as an allophone speech synthesis system, are not sufficiently fast and typically produce low quality speech. Devices that only repeat the same (or slightly varying) information, such as a depth detecting device that periodically outputs the sensed depth through an allophone speech synthesizer, are not sufficiently versatile. Devices that employ prerecordings of entire sentences (including all possible combinations of numbers) require a great deal of memory and are consequently either very slow or prohibitively expensive.
It is an object of the invention to provide a flexible yet inexpensive high quality speech synthesis system for providing speech synthesized output of navigational information from a variety of equipment.
It is a further object of the invention to provide a speech synthesis system that utilizes a limited but large number of predefined words or phrases, and provides realistic human speech at a natural speed.